1. Field of the Invention
The present invention relates to a liquid jet head unit including a liquid jet head ejecting liquids to be injected, to a manufacturing method thereof, and to a liquid jet device. Particularly, the present invention relates to an ink-jet recording head unit including an ink-jet recording head in which a part of pressure generating chambers which communicate with nozzle orifices ejecting ink droplets is formed of a vibration plate, piezoelectric elements are provided on this vibration plate and the ink droplets are ejected by displacement of the piezoelectric elements. In addition, the present invention relates to a method for manufacturing the ink-jet recording head unit and an ink-jet recording apparatus.
2. Description of the Related Art
An ink-jet recording apparatus such as an ink-jet printer and a plotter has an ink-jet recording head unit (hereinafter referred to as a head unit) which includes an ink-jet recording head capable of ejecting ink stored in an ink reservoir such as an ink cartridge and an ink tank, as ink droplets.
The head unit includes: an ink-jet recording head which has nozzle arrays including arranged nozzle orifices; a head case fixed to an ink supply port side of the ink-jet recording head; and a cover head which protects an ink droplet ejecting surface side of the ink-jet recording head. The cover head has: a window frame part having an open window portion which is provided on the ink droplet ejecting surface side of the ink-jet recording head and exposes the nozzle orifices; and a sidewall part which is formed to be bent toward a side face of the ink-jet recording head from the window frame part. The cover head is fixed to the ink-jet recording head by joining the sidewall part to the side face of the ink-jet recording head (for example, refer to Japanese Patent Laid-Open No. 2002-160376 (Page 4, FIG. 3)).
Moreover, there has been proposed a head unit in which a cover head is fixed to a surface of a member different from nozzles of an ink-jet recording head so that the ink-jet recording head is fixed by use of the cover head (for example, refer to Japanese Patent Laid-Open No. 2003-145791 (Page 6, FIGS. 6 and 7)).
However, in an ink-jet recording head including multiple nozzle arrays in which nozzle orifices are arranged, if multiple arrays of nozzle orifices are provided in one ink-jet recording head, there arises a problem that yield is reduced.
Moreover, if there is a space between the ink droplet ejecting surface and the cover head, a difference in level between the ink droplet ejecting surface and the cover head is increased. Thus, even if the ink droplet ejecting surface is wiped, there is a problem that this difference in level causes ink to remain on the ink droplet ejecting surface and the ink enters the space. Furthermore, if there is a space between the ink droplet ejecting surface and the cover head, there is a problem that media to be recorded on such as paper get into the space to cause occurrence of paper jams and deformation of the cover head.
Moreover, when multiple nozzle arrays are provided by using a plurality of ink-jet recording heads in a head unit, there arises the following problem. Specifically, in fixing the plurality of ink-jet recording heads to a retaining member such as a cartridge case in which ink cartridges are mounted, relative positioning of adjacent nozzle arrays cannot be accurately performed. Moreover, when a retaining member retaining a head unit is mounted on a carriage which moves in a scanning direction of a medium to be recorded on, it is required to perform positioning of the retaining member and the carriage in order to perform relative positioning of the carriage and nozzle arrays. Moreover, there is a problem that positioning of the nozzle arrays with respect to the carriage cannot be accurately performed.
Furthermore, when the cover head is joined to a surface of a member different from the nozzles, there arises the following problem. Specifically, an operation of positioning the cover head and the nozzle arrays and joining them is difficult. Moreover, highly accurate positioning thereof cannot be performed.
Note that such problems as described above exist not only in the ink-jet recording head unit including the ink-jet recording head ejecting ink but also in a liquid jet head unit including another liquid jet head ejecting a substance other than ink, as a matter of course.